The invention relates to high-impact resistant tools, or impact tools, such as those installed in machinery used in a high impact-type service or operation, such as earth-boring drill bits. These tools are commonly subjected to high impact loads, vibrations, high temperatures and pressures, and other adverse conditions. Frequent replacement of the high-impact resistant tools is undesirable, though often necessary due to spalling, delamination, and abrasive wear. Accordingly, efforts have been made to increase the life of such tools.
Such efforts are disclosed in U.S. Pat. No. 4,109,737 to Bovenkerk, which is herein incorporated by reference for all that it contains. Bovenkerk discloses a rotary drill bit for rock drilling comprising a plurality of cutting elements mounted by interference-fit in recesses in the crown of the drill bit. Each cutting element comprises an elongated pin with a thin layer of polycrystalline diamond bonded to the free end of the pin.
U.S. Pat. No. 5,544,713 to Dennis, which is herein incorporated by reference for all that is contains, discloses a cutting element which has a metal carbide stud having a conic tip formed with a reduced diameter hemispherical outer tip end portion of the metal carbide stud. A layer of polycrystalline material, resistant to corrosive and abrasive materials, is disposed over the outer end portion of the metal carbide stud to form a cap. An alternate conic form has a flat tip face. A chisel insert has a transecting edge and opposing flat faces. It is also covered with a PDC layer.
U.S. Pat. No. 6,484,826 to Anderson which is herein incorporated by reference for all that it contains, discloses enhanced inserts are formed having a cylindrical grip and a protrusion extending from the grip. An ultra hard material layer is bonded on top of the protrusion. The inserts are mounted on a rock bit and contact the earth formations off center. The ultra hard material layer is thickest at a critical zone which encompasses a major portion of the region of contact between the insert and the earth formation. Transition layers may also be formed between the ultra hard material layer and the protrusion so as to reduce the residual stresses formed on the interface between the ultra hard material and the protrusion.
U.S. Pat. No. 5,848,657 by Flood et al., which is herein incorporated by reference for all that it contains, discloses domed polycrystalline diamond cutting element wherein a hemispherical diamond layer is bonded to a tungsten carbide substrate, commonly referred to as a tungsten carbide stud. Broadly, the inventive cutting element includes a metal carbide stud having a proximal end adapted to be placed into a drill bit and a distal end portion. A layer of cutting polycrystalline abrasive material is disposed over the distal end portion such that an annulus of metal carbide adjacent and above the drill bit is not covered by the abrasive material layer.